With fast growing use and popularity of multimedia and communication services, demand for faster and more reliable wireless communication services is also increasing at a fast rate. In order to accommodate such changing demands, the capacity of the wireless communication system needs to improve as well. To this end, the capacity can be improved by better utilizing and increasing the efficiency of the existing limited wireless resources.
As an example of improving the use of the existing limited wireless resources, a transmitter and a receiver can respectively be equipped with more than one antenna. With more than one antenna, diversity gain can be achieved with respect to spatial domain, and transmit diversity can be increased by transmitting data via each antenna in parallel.